Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Surabaya to Tonga as you normally would.
Related info for your journey
Useful info, stats and facts about Surabaya to Tonga flights.
Located just 15.0 km from the city centre, Surabaya Juanda (SUB) is the airport most travellers will use when flying to Tonga from Surabaya.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Surabaya Juanda Airport to Nuku‘alofa Fua'Amotu Intl Airport flight would often be abbreviated as a SUB to TBU flight. Vava'u Lupepau'U Airport (VAV) are some additional IATA codes for airports related to your trip.